Florian Lohoff wrote: > On Fri, Apr 21, 2006 at 01:07:13AM +0200, Ulrich Teichert wrote: > > [trimmed the cc list a bit] > > >> It would also make it difficult to netboot a DECstation - the firmware > > >> only boots ECOFF kernels. I don't know if it will break delo (the > > >> DECstation boot loader), too. > > > > > >Delo uses ELF. Netbooting a DECstation works via a t-rex generated > > >image which fakes an ECOFF header. > > > > Ah, good to know. > > addition - The Decstations firmware boots a binary blob to an address > specified in the first 512bytes of the boot disk. There no format just > binary instructions. Delo which gets copied with objdump to that blob > itself knows how to boot ELF. So for disk booting the decstations does > not need ECOFF.
Early versions of Delo probably used to do that, but the current one uses the firmware loader in a more sophisticated way. The firmware expects in a certain part of the first 512 bytes a list of offset/size pairs describing disk blocks, which it loads to a load address also specified there. The whole scheme was intended for Ultrix disklabels, but happens to fit in a DOS partition table, where it uses some of the space where a PC BIOS would expect executable code. The /sbin/delo analyses the next stage bootloader /boot/delo.2nd, which is an ELF file, and writes the offset/size list of its binary contents to the aforementioned 512 bytes. No objcopy involved, no raw binary, no second copy of the loader. :-) The same works for iso9660 images, btw. Thiemo -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
